There are conventionally used management devices that store measurement data on a network or store resource measurement data on server system in databases (DB) and retain the data in databases in accordance with the type of measurement data. For example, such management devices manage the retention period of the measurement data such that the measurement data accumulated every minute is retained in a database for three months or such that the measurement data accumulated every one hour is retained in a database for one year. Furthermore, such management devices manage the retention period of the measurement data such that the measurement data accumulated every day is retained in a database for three years. Furthermore, such management devices manage important measurement data such that the important measurement data is indefinitely retained in a database without setting the retention period.
When a problem occurs, network administrators or server system administrators specify the cause of the problem by checking the contents of the measurement data retained in the database. Management devices delete measurement data from a database after the retention period expires.
Patent Document 1: Japanese Laid-open Patent Publication No. 09-016440
Patent Document 2: Japanese Laid-open Patent Publication No. 08-077332
Patent Document 3: Japanese Laid-open Patent Publication No. 10-301817
Patent Document 4: Japanese Laid-open Patent Publication No. 10-011330
However, with the conventional technology described above, there is a problem in that a spare retention area, which is a free memory area, in a database is not effectively used. For example, if the retention period during which measurement data is retained in a database is previously set, there may sometimes be a case in which a spare retention area is present in a memory area in a database. In such a case, because measurement data is not retained in the spare retention area, the spare retention area is not effectively used.
In the following, a reason for needing such a spare retention area will be described. Even when the size of measurement data to be retained increases, by using another spare retention area as an area in which the measurement data is retained, the retention period of various measurement data can be more reliably reserved.
In the following, a description will be given with reference to FIG. 36 and by using examples of “per-day data”, which is measurement data accumulated every day; “per-hour data”, which is measurement data accumulated every one hour; “per-minute data”, which is measurement data accumulated every minutes; and “important data”, which is important measurement data contained in the above data.
FIG. 36 is a schematic diagram illustrating a problem with the conventional technology. In the example illustrated in FIG. 36, the “per-day data”, the “per-hour data”, the “per-minute data”, and the “important data” are stored in a database. Furthermore, in the example illustrated in FIG. 36, the retention periods for the “per-day data”, the “per-hour data”, the “per-minute data”, and the “important data” are three years, one year, three months, and indefinitely, respectively. FIG. 36 illustrates a case in which, if the retention periods for the “per-day data”, the “per-hour data”, the “per-minute data”, and the “important data” are three years, one year, three months, and indefinitely, respectively, a spare retention area 91 corresponding to a free memory area is present in a memory area 90 in the database.
As described above, with the conventional technology, there is a problem in that, if the retention period of the database measurement data to be retained in the database is previously set, it is not possible to effectively use a spare retention area that is a free memory area.
Furthermore, to avoid the presence of the spare retention area, if the entire memory area in the database is allocated to areas for each measurement data and each measurement data is retained in each area, the following problem occurs due to insufficient memory area if the size of any of the measurement data becomes large.
Specifically, there may sometimes be a problem in which the measurement data is not retained for the retention period that is previously set. In the following, this problem will be specifically described. FIG. 37 is a schematic diagram illustrating a problem that occurs when the entire memory area of a database is allocated to areas for each measurement data and each of the measurement data is retained in each region.
In the example illustrated in FIG. 37, “per-day data”, “per-hour data”, “per-minute data”, and “important data” are stored in a database. Furthermore, FIG. 37 illustrates a case, as an example, in which, to avoid the presence of the spare retention area, an entire memory area 90A in the database is allocated such that the retention periods of the “per-day data”, the “per-hour data”, the “per-minute data”, and the “important data” are 4.5 years, 1.5 years, 4.5 months, and indefinitely, respectively. In such a case, a management device manages an operation that satisfies a predetermined operation condition, e.g., the condition that the “per-minute data” be always retained for 4.5 months, which is the retention period of the “per-minute data”. As illustrated in FIG. 37, if the size of the “per-minute data” becomes large, the following problem may occur. The retention periods of the “per-day data” and the “per-hour data” become 2.4 years and 0.8 years, respectively. Accordingly, there may be a problem in that the “per-day data” and the “per-hour data” are not retained for three years and one year, respectively, that is the minimum retention period.